1. Field of the Invention
This invention relates to service fittings.
2. Description of the Background Art
In one form of conventional service fitting, a service hose is connected to a refrigeration air conditioning system through a core valve-type service fitting provided on the system. The conventional connections are effected by threaded means on the hose fitting and service fitting, respectively. A core depressor is provided in the hose end fitting to open the core valve as the fluid connection is being made.
A serious problem arose in such fittings in that because of variability in the positioning of the core valves, the core depressors did not, in all cases, suitably open the core valve when the fittings were connected. To remedy this problem, it has been suggested to provide an adjustable core depressor which is manually adjusted to compensate for variation in the core valve positions. Such adjustment may be effected when necessary, such as when a connection is made without suitably opening the core valve. Obviously, such constant adjustment of the core valve depressor, while solving the original problems, still is not a fully satisfactory answer because of the need for the selective adjustment at times.
Another problem found in the existing service connections arises in the use of the threaded connecting means. Such threaded connecting means do not constitute quick-connect means and commonly refrigerant is lost during the threaded connection between the fittings before the sealed connection is completed.
Another problem arising with the threaded connecting means is the difficulty at times in properly aligning the threads of the stiffness of the hose.
A number of quick-connect couplings have been developed over the years. One such coupling is illustrated in U.S. Pat. No. 3,174,508 of Jerry J. Zahuranec, wherein a double-end shut-off quick-connect tube coupling is provided. The female valve is a ball check valve and is engaged by the stem of the male connector, which is spring-biased. Positive sequential action of the shutoff valve is provided for preventing substantial flow into the coupling until a sealing and locking engagement is assured. A quickconnect retaining means is provided comprising a spring-urged sleeve and ball detent.
Somewhat similar quick-connect couplers are illustrated in R. P. Jacques U.S. Pat. No. 1,383,306 and James R. Johnston U.S. Pat. No. 3,435,848. In the Johnston patent, the quick-connect means comprise springy fingers latched by a slide sleeve.
George F. Hupp shows, in U.S. Pat. No. 3,267,963, a hydraulic coupler wherein two check valves engage each other in the connected arrangement so as to become spaced from their respective seats in the open condition. One of the springs is stronger than the other so as to provide a differential opening action.